The disclosure concerns anti-cavitation constructions of a liquid ring pump.
Liquid ring pumps and their operation are well known. In general liquid ring pumps utilize a liquid ring which, during operation, delimits a pumping chamber. The pumping chamber can comprise one or multiple lobes. A shaft rotates a rotor. The liquid ring is eccentric. During operation of the pump a radial inward surface of the liquid ring is radially spaced from the shaft at an intake zone to allow buckets formed by adjacent blades of the rotor to fill with gas entering the pump's pumping chamber through an inlet port. The inlet port is downstream of a pump head inlet. The buckets fill with gas as they sweep past the inlet port. An inlet port channel extends from the inlet port and provides a fluid connection between the pump head inlet and the inlet port.
The radial inward surface of the liquid ring in a compression zone of the pump is oriented relative to the shaft to compress the gas in the buckets and force the gas through an outlet port which leads to an outlet of the pump. An outlet port channel extends from the outlet port and provides a fluid connection between the outlet port and the pump head outlet.
The ring compresses the gas in the buckets because of its eccentric orientation. The orientation means the radially inward surface of the liquid ring has a much closer approach to the axis of the shaft in the radial direction along the compression zone as compared to its approach along the intake zone.
During operation of the pump, sealing liquid is introduced into the buckets. The sealing liquid enters a bucket of the pump through a sealing liquid introduction port formed in the outer sidewall. A sealing liquid introduction channel extends to the sealing liquid introduction port and provides a fluid connection between a pump head sealing liquid inlet to the sealing liquid introduction port. The sealing liquid enters the buckets from the sealing liquid introduction port. The sealing liquid fills interstices and otherwise allows for proper operation of the pump such as replenishing the liquid forming the liquid ring.
The sealing liquid in the bucket can cause cavitation of the blades and in particular at the base of a leading side of a trailing blade forming the bucket. To reduce the damage caused by cavitation, the art has used material resistant to cavitation. The art has also used diverters proximate the sealing liquid introduction port in the port member to reduce cavitation. U.S. Pat. No. 4,498,844, Bissell provides a comprehensive description of how a liquid ring pump having a conical or cylindrical port member operates and some of its basic structure and is hereby fully incorporated by reference.